Focus on Cellulose ethers

Indima ye-cellulose ether kwi-powder mortar eyomileyo

I-Cellulose ether yipolymer yokwenziwa eyenziwe kwi-cellulose yendalo ngokuguqulwa kweekhemikhali. I-ether ye-cellulose iphuma kwi-cellulose yendalo. Ukuveliswa kwe-cellulose ether kuyahluka kwiipolymers zokwenziwa. Izinto zayo ezisisiseko ziyi-cellulose, i-polymer compound yendalo. Ngenxa yobungcali besakhiwo se-cellulose yendalo, i-cellulose ngokwayo ayinakho ukusabela kunye nee-etherification agents. Nangona kunjalo, emva kokunyangwa kwe-ejenti yokuvuvukala, iibhondi ze-hydrogen ezomeleleyo phakathi kwamatyathanga e-molecular kunye namatyathanga atshatyalaliswa, kwaye ukukhutshwa okusebenzayo kweqela le-hydroxyl kuba yi-alkali cellulose esebenzayo. Fumana i-cellulose ether.

Iimpawu ze-cellulose ethers zixhomekeke kuhlobo, inani kunye nokuhanjiswa kwezinto ezithatha indawo. Ulwahlulo lwe-cellulose ethers lukwasekelwe kuhlobo lwabaxumi, i-degree of etherification, i-solubility kunye neepropati ezinxulumene nesicelo. Ngokohlobo lwababambeleyo kwitsheyini yemolekyuli, inokwahlulwa ibe yi-monoether kunye ne-ether edibeneyo. Sidla ngokusebenzisa i-mc njenge-monoether, kunye ne-HPmc njenge-ether exutywe. I-Methyl cellulose ether mc yimveliso emva kweqela le-hydroxyl kwiyunithi ye-glucose ye-cellulose yendalo ifakwe endaweni yeqela le-methoxy. Yimveliso efunyenwe ngokutshintsha inxalenye yeqela le-hydroxyl kwiyunithi kunye neqela le-methoxy kunye nenye inxalenye kunye neqela le-hydroxypropyl. Ifomula yolwakhiwo ithi [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)CH3]n]x Hydroxyethyl methyl cellulose ether HEmc, ezi zezona ntlobo zisetyenziswa kakhulu kwaye zithengiswa kwimarike.

Ngokubhekiselele kwi-solubility, inokwahlulwa ibe yi-ionic kunye ne-non-ionic. Ii-ether ze-cellulose ezingenayo i-ionic ezinyibilikayo zamanzi zenziwa ikakhulu ngamacandelo amabini e-alkyl ethers kunye ne-hydroxyalkyl ethers. I-Ionic Cmc isetyenziswa ikakhulu kwizicoci zokwenziwa, ukuprintwa kwelaphu kunye nokudaya, ukutya kunye nokuhlola ioli. I-non-ionic mc, i-HPmc, i-HEmc, njl. zisetyenziswa kakhulu kwizinto zokwakha, iingubo ze-latex, amayeza, iikhemikhali zemihla ngemihla, njl njl. Isetyenziswe njenge-thickener, i-agent yokugcina amanzi, i-stabilizer, i-dispersant kunye ne-agent yokwenza ifilimu.

Ukugcinwa kwamanzi kwe-cellulose ether

Ekuvelisweni kwezinto zokwakha, ngakumbi udaka oluxubeneyo olomileyo, i-cellulose ether idlala indima engenakuphinda ithathelwe indawo, ngakumbi kwimveliso yodaka olukhethekileyo (udaka olulungisiweyo), luyinto eyimfuneko kwaye ibalulekileyo.

Indima ebalulekileyo ye-ether ye-cellulose e-soluble yamanzi kwi-mortar ikakhulu inemiba emithathu, enye inamandla okugcina amanzi, enye yimpembelelo ehambelanayo kunye ne-thixotropy yodaka, kwaye okwesithathu kukusebenzisana nesamente.

Ukugcinwa kwamanzi kwi-ether ye-cellulose kuxhomekeke ekufunjweni kwamanzi kwinqanaba lesiseko, ukubunjwa kodaka, ubukhulu bodaka lodaka, imfuno yamanzi yodaka, kunye nexesha lokumisela izinto zokumisela. Ukugcinwa kwamanzi kwe-cellulose ether ngokwayo kuvela kwi-solubility kunye nokuphelelwa ngamanzi kwe-cellulose ether ngokwayo. Njengoko sonke sisazi, nangona i-cellulose i-molecular chain iqulethe inani elikhulu lamaqela e-OH anamandla, ayinyibiliki emanzini, kuba isakhiwo se-cellulose sinezinga eliphezulu le-crystallinity. Isakhono se-hydration samaqela e-hydroxyl iyodwa akwanelanga ukugubungela iibhondi ze-hydrogen ezomeleleyo kunye ne-van der Waals phakathi kwee-molecule. Ngoko ke, idumba kuphela kodwa ayinyibiliki emanzini. Xa i-substituent ingeniswa kwitsheyina le-molecular, kungekhona nje i-substituent etshabalalisa ikhonkco le-hydrogen, kodwa kunye ne-interchain ye-hydrogen bond iyatshatyalaliswa ngenxa yokutshatyalaliswa kwe-substituent phakathi kwamatyathanga akufutshane. Ubukhulu be-substitute, umgama omkhulu phakathi kweemolekyuli. Umgama mkhulu. Umphumo omkhulu wokutshabalalisa iibhondi ze-hydrogen, i-ether ye-cellulose iba yi-soluble yamanzi emva kokuba i-cellulose lattice yanda kwaye isisombululo singena, senza isisombululo esiphezulu se-viscosity. Xa izinga lokushisa liphakama, i-hydration ye-polymer iyancipha, kwaye amanzi phakathi kwamaketanga akhutshwa ngaphandle. Xa isiphumo sokuchithwa kwamanzi sanele, iamolekyu ziqala ukudibanisa, zenza i-gel yesakhiwo senethiwekhi ye-dimensional emithathu kwaye ihlanganiswe ngaphandle. Izinto ezichaphazela ukugcinwa kwamanzi kwi-mortar ziquka i-viscosity ye-cellulose ether, inani elongezelelweyo, ukucocwa kweengqungquthela kunye nokushisa kokusetyenziswa.

Ukuphakama kwe-viscosity ye-cellulose ether, ngcono ukusebenza kokugcinwa kwamanzi, kunye nokuphakama kwe-viscosity yesisombululo se-polymer. Ngokuxhomekeke kubunzima bemolekyuli (i-polymerization degree) yepolymer, iphinda igqitywe ngobude be-chain yesakhiwo se-molecular kunye nokumila kwekhonkco, kunye nokuhanjiswa kweentlobo kunye nobuninzi bezinto ezithintekayo nazo zichaphazela ngokuthe ngqo uluhlu lwe-viscosity. [η]=Kmα

[η] I-viscosity yangaphakathi yesisombululo sepolymer
m polymer ubunzima bemolekyuli
α ipholima yophawu olungaguqukiyo
K i-viscosity isisombululo se-coefficient

I-viscosity yesisombululo sepolymer ixhomekeke kubunzima be-molecular of polymer. I-viscosity kunye nokuxinwa kwesisombululo se-cellulose ether ihambelana nesicelo kwiinkalo ezahlukeneyo. Ke ngoko, i-ether yeselulosi nganye ineenkcazo ezininzi ezahlukeneyo ze-viscosity, kwaye uhlengahlengiso lwe-viscosity lubonakaliswa ikakhulu ngokuthotywa kwe-alkali cellulose, oko kukuthi, ukuqhawuka kwamakhonkco e-cellulose.

Ubuninzi be-ether ye-cellulose eyongeziweyo kwidaka, ngcono ukugcinwa kwamanzi, kunye nokuphakama kwe-viscosity, ngcono ukugcinwa kwamanzi.

Ubungakanani be-particle, i-fineral particle, ngcono ukugcinwa kwamanzi (jonga umfanekiso 3). Emva kokuba amasuntswana amakhulu e-cellulose ether adibane namanzi, umphezulu uyanyibilika ngokukhawuleza kwaye wenze ijeli ukusonga izinto zokuthintela iimolekyuli zamanzi ukuba zingaqhubeki nokungena. Ngamanye amaxesha ayinakuchithwa ngokulinganayo kwaye inyibilikiswe nasemva kwexesha elide, ukwenza isisombululo esinamafu okanye i-agglomeration. Ichaphazela kakhulu ukugcinwa kwamanzi kwe-cellulose ether, kwaye ukunyibilika yenye yezinto zokukhetha i-cellulose ether.

Ukutyeba kunye Thixotropy yeCellulose Etere

Umsebenzi wesibini we-cellulose ether - ukuqina kuxhomekeke kwi: iqondo le-polymerization ye-cellulose ether, i-concentration concentration, i-shear rate, iqondo lokushisa kunye nezinye iimeko. Ipropati ye-gelling yesisombululo iyingqayizivele kwi-alkyl cellulose kunye ne-derivatives yayo eguqulwayo. Iimpawu ze-gelation zihambelana neqondo lokutshintshwa, ukugxininiswa kwesisombululo kunye nezongezo. Kwiimveliso eziguqulweyo ze-hydroxyalkyl, iipropati zejeli nazo zihambelana neqondo lokuguqulwa kwe-hydroxyalkyl. Kwi-mc kunye ne-HPmc ene-viscosity ephantsi, isisombululo se-concentration ye-10% -15% sinokulungiswa, isisombululo se-5% -10% sinokulungiswa kwi-medium viscosity mc kunye ne-HPmc, kunye ne-2% -3% isisombululo sinokulungiswa kwi-viscosity mc ephezulu kunye HPmc, kwaye ngokuqhelekileyo Ukuhlelwa kwe-viscosity ye-ether ye-cellulose iphinda ihlelwe nge-1% -2% isisombululo. Ubunzima bemolekyuli ephezulu ye-cellulose ether inokuqina okuphezulu. Kwisisombululo esifanayo soxinaniso, iipolymers ezinobunzima beemolekyuli ezahlukeneyo zinee-viscosities ezahlukeneyo. Iqondo eliphezulu. I-viscosity ekujoliswe kuyo inokufezekiswa kuphela ngokongeza inani elikhulu le-ether ye-cellulose ephantsi ye-molecular weight. I-viscosity yayo inokuxhomekeka okuncinci kwireyithi yokucheba, kwaye i-viscosity ephezulu ifikelela kwi-viscosity ekujoliswe kuyo, kwaye inani elifunekayo lokongeza lincinci, kwaye i-viscosity ixhomekeke ekusebenzeni kakuhle. Ngoko ke, ukufezekisa ukuhambelana okuthile, inani elithile le-cellulose ether (ukugxilwa kwesisombululo) kunye ne-viscosity yesisombululo kufuneka kuqinisekiswe. Iqondo lokushisa le-gel yesisombululo liyancipha ngokuhambelana nokunyuka koxinzelelo lwesisombululo, kunye neegels kwiqondo lokushisa emva kokufikelela kwinqanaba elithile. I-concentration ye-gelation ye-HPmc iphezulu kwiqondo lokushisa.

Ukuhambelana kungalungiswa ngokukhetha ubungakanani besuntswana kunye nokukhetha i-cellulose ethers ngeedigri ezahlukeneyo zokuguqulwa. Into ebizwa ngokuba luhlengahlengiso kukwazisa iqondo elithile lokutshintshwa kwamaqela e-hydroxyalkyl kulwakhiwo lwamathambo e-mc. Ngokutshintsha amaxabiso ahambelanayo atshintshileyo amabini abambeleyo, oko kukuthi, i-DS kunye ne-ms ehambelanayo amaxabiso e-methoxy kunye ne-hydroxyalkyl esihlala siyithetha. Iimfuno ezahlukeneyo zokusebenza ze-cellulose ether zinokufunyanwa ngokutshintsha amaxabiso ahambelanayo ahambelanayo amabini abambeleyo.

I-cellulose ethers esetyenziswe kwizinto zokwakha ezinomgubo kufuneka ichithe ngokukhawuleza emanzini abandayo kwaye inike ukuhambelana okufanelekileyo kwesistim. Ukuba kunikwe umlinganiselo othile wokucheba, isuka ibe yibloko ejikelezayo kunye ne-colloidal, eyimveliso ekumgangatho ophantsi okanye ekumgangatho ophantsi.

Kukwakho nobudlelwane obuhle bomgca phakathi kokungaguquguquki kwentlama yesamente kunye nedosi ye-cellulose ether. I-ether ye-cellulose inokunyusa kakhulu i-viscosity yodaka. Ubukhulu bedosi, kokukhona isiphumo sicaca ngakumbi, jonga uMfanekiso 6

I-high-viscosity cellulose ether isisombululo samanzi sine-thixotropy ephezulu, ekwayimpawu enkulu ye-cellulose ether. Izisombululo ezimanzi ze-Mc-type polymers zihlala zine-pseudoplastic kunye ne-non-thixotropic fluidity ngaphantsi kobushushu bejeli yazo, kodwa iipropati ezihamba ngeNewtonian kumazinga aphantsi okucheba. I-Pseudoplasticity iyanda kunye nobunzima be-molecular okanye i-concentration ye-cellulose ether, kungakhathaliseki ukuba luhlobo luni lwe-substitute kunye neqondo lokutshintshwa. Ngoko ke, i-cellulose ethers yebakala elifanayo le-viscosity, kungakhathaliseki ukuba i-mc, i-HPmc, i-HEmc, iya kuhlala ibonisa iimpawu ezifanayo ze-rheological nje ngokuba ugxininiso kunye nobushushu bugcinwa rhoqo. Iigels zesakhiwo zenziwe xa ubushushu buphakanyisiwe, kwaye ukuhamba okuphezulu kwe-thixotropic kwenzeka. Uxinzelelo oluphezulu kunye ne-viscosity ephantsi ye-cellulose ethers ibonisa i-thixotropy nangaphantsi kweqondo lokushisa le-gel. Lo mhlaba unenzuzo enkulu kuhlengahlengiso lomgangatho kunye nokuncipha kulwakhiwo lodaka lwesakhiwo. Kufuneka kucaciswe apha ukuba i-viscosity ephezulu ye-ether ye-cellulose, ngcono ukugcinwa kwamanzi, kodwa ukuphakama kwe-viscosity, ukuphakama kwe-molecular weight ye-cellulose ether, kunye nokuncipha okuhambelanayo kwi-solubility yayo, enefuthe elibi. kugxininiso lodaka kunye nokusebenza kolwakhiwo. Ukuphakama kwe-viscosity, kuyabonakala ngakumbi umphumo wokuqina kumdaka, kodwa awulingani ngokupheleleyo. Enye i-viscosity ephakathi kunye nephantsi, kodwa i-ether ye-cellulose eguqulwayo inomsebenzi ongcono ekuphuculeni amandla okwakhiwa kodaka olumanzi. Ngokunyuka kwe-viscosity, ukugcinwa kwamanzi kwe-cellulose ether kuphucula.


Ixesha lokuposa: Nov-22-2022
Incoko ka-WhatsApp kwi-Intanethi!